1. The flame-retardant low-release layer stranded optical cable is characterized by comprising a reinforcing structural member positioned in the center of the cable, wherein a plurality of optical fiber units are wound around the outer edge of the reinforcing structural member along the edge of the reinforcing structural member, a metal composite belt is wound around the plurality of optical fiber units, and cable core fillers and cable opening ropes are filled in gaps between the plurality of optical fiber units and the metal composite belt; the metal composite belt is wrapped with a flame-retardant belt, the flame-retardant belt is provided with a plastic extrusion foaming cushion layer, and the flame-retardant sheath is extruded outside the foaming cushion layer.

2. The flame-retardant low-release layer-stranded optical cable according to claim 1, wherein: the reinforced structural part is composed of a reinforced element and a flame-retardant cushion layer extruded outside the reinforced element.

3. The flame-retardant low-release layer-stranded optical cable according to claim 1, wherein: the optical fiber unit comprises a loose tube, a plurality of optical fibers are arranged in the loose tube, and fillers in the tube are filled between the loose tube and the optical fibers.

4. The flame-retardant low-release layer-stranded optical cable according to claim 1, wherein: the flame-retardant belt is formed by pressing a flame-retardant sheath material into a rectangular plate, and a magnalium flame-retardant film is attached to the plate through glue.

5. The flame-retardant low-release layer-stranded optical cable according to claim 1, wherein: a plurality of holes are uniformly distributed in the foaming cushion layer and the flame-retardant sheath by taking the center of the optical cable as a central point, and nitrogen is injected into the holes.

6. The flame-retardant low-release layer-stranded optical cable according to claim 1, wherein: the foamed cushion layer has density less than 0.8g/cm³The material is extruded.

7. The preparation method of the flame-retardant low-release object layer stranded optical cable according to any one of claims 1 to 6, characterized by comprising the following steps:

1) stably releasing the optical fiber through a pay-off rack, wherein the pay-off tension of the optical fiber is less than 80N, curing the optical fiber through a coloring mold and a curing channel, removing static electricity through a static electricity removing device, and collecting the colored optical fiber on a disc;

2) a plurality of colored optical fibers are steadily released through active paying-off, the paying-off tension is 80N-100N, a PBT loose tube is extruded outside the optical fibers while paying-off is carried out, an optical fiber unit is formed, the paying-off tension can be properly adjusted according to the surplus length of the loose tube, and the surplus length is 0-0.5 per mill; wherein the extrusion molding process adopts a temperature difference method for production, and in order to ensure the full crystallization of a product, the product needs to be cooled by a hot water tank and a cold water tank which are arranged in front and at the back, the water temperature difference of the cold water tank is 45 ℃, the temperature difference is controlled within 5 ℃, the hot water tank is set to be 60 ℃, and the cold water tank is set to be 15 ℃; the hot water tank is internally provided with a section of annular pipeline, four water outlets which are evenly distributed according to 360 degrees and are provided with pressure regulating valves are arranged in the pipeline, water pressure impact is carried out on the PBT loose tube at the hot water tank section, the pressure regulating valves ensure that the water flushed out from the water outlets has controllable pressure, the water pressure impact is used for increasing the extra length of the PBT loose tube at the hot water tank section, the length of the cold water tank is set to be 25 m, 2 turning guide wheels are added for fully cooling and crystallizing, the cooling length of the loose tube is expanded to be more than 100 m, the full crystallization of a product is ensured, and the influence of 2 times of crystallization on the extra length again is avoided;

3) the reinforced structural member, the optical fiber units and the cable opening rope are twisted into a cable core through a twisting machine, and stable paying-off is carried out through a paying-off device, wherein the paying-off tension is not larger than 180N;

4) the metal composite belt for embossing treatment is wrapped outside the cable core, and the size of the forming grinding tool for embossing treatment is as follows: the diameter of the cable core is +1 mm;

5) wrap the fire-retardant area on metal composite belt, wrap the package overlap joint for 5% around the package pitch, and the cable core after wrapping passes through mold core, die sleeve and gets into the extruding machine aircraft nose and carry out the extrusion molding, and the extrusion molding material is medium density PE material, and the heating section divides multistage fuselage and multistage aircraft nose, and the fuselage temperature is respectively: 130 ℃, 140 ℃, 150 ℃, 155 ℃ and 160 ℃, and the head temperature is respectively as follows: at 170 ℃, 170 ℃ and 180 ℃, the cable core is dragged through a central hole of a mold core during production, 12 core pipes are arranged on the mold core around the central hole, 12 corresponding holes are formed in the foaming cushion layer after extrusion molding in a pipe extrusion mold mode, 12 corresponding injection pipes are arranged on a pressure mold gun, nitrogen is quantitatively injected into the corresponding holes through pressure control, the foaming cushion layer is formed after cooling through a cooling water tank, and a finished product is collected on a disc;

6) the cable core that contains the foaming bed course with above-mentioned extrusion molding carries out steady unwrapping wire through pay-off, and unwrapping wire tension is not more than 180N, and the cable core that contains the foaming bed course passes through mold core, die sleeve and gets into the aircraft nose and carries out the extrusion molding, and the extrusion molding material is the fire-retardant PE of low release amount, and the heating section divides multistage fuselage and multistage aircraft nose, and the fuselage temperature is respectively: 150 ℃, 170 ℃, 180 ℃, 190 ℃ and 200 ℃, and the head temperatures are respectively as follows: the production process includes drawing the cable core through the central hole of the mold core, extruding 12 pipe cores around the central hole, forming 12 holes in the foamed cushion layer, injecting nitrogen gas via pressure control into the holes, cooling in water cooling tank and collecting the product in the disc.

8. The method for preparing a flame-retardant low-release layered-stranded optical cable according to claim 7, wherein the core and the die sleeve in the steps 6) and 7) are of a tube-extruding structure, the core is provided with a central hole in the center, and 12 core tubes are uniformly distributed around the central hole for forming holes by extrusion.

9. The method for preparing the flame-retardant low-release layered-stranded optical cable according to claim 7, wherein the cable core can be easily drawn out of the metal composite tape after the metal composite tape is molded in the step 4).

Background

With the development of 5G networks and the wide application of intelligent manufacturing, the application scenes of the optical cable are gradually expanded from forests, hills, lakes and oceans in wide areas to cities, communities, buildings and even families of each family, and the conversion of the use scenes provides new requirements for the optical cable.

With the proposal of flame retardant performance, the existing various types of flame retardant optical cables appear in the field of view of the public, but the methods of complicated structure, multi-layer wrapping and filling of flame retardant substances exist. However, the structure not only increases the cost, but also has more released substances after combustion, the bending performance cannot be effectively guaranteed, and the weight of the optical cable is correspondingly increased, so that the construction and the laying are inconvenient.

Disclosure of Invention

The invention provides a flame-retardant low-release object layer stranded optical cable for solving the existing problems.

The invention also provides a preparation method of the flame-retardant low-release object layer stranded optical cable.

The invention relates to a flame-retardant low-release layered stranded optical cable which comprises a reinforced structural member positioned in the center of the cable, wherein a plurality of optical fiber units are wound around the outer edge of the reinforced structural member along the edge of the reinforced structural member, metal composite belts are wound around the plurality of optical fiber units, and cable core fillers and cable opening ropes are filled in gaps between the plurality of optical fiber units and the metal composite belts; the metal composite belt is wrapped with a flame-retardant belt, the flame-retardant belt is provided with a plastic extrusion foaming cushion layer, and the flame-retardant sheath is extruded outside the foaming cushion layer.

In a further improvement, the reinforced structural member is composed of a reinforcing element and a flame-retardant cushion layer extruded outside the reinforcing element.

In a further improvement, the optical fiber unit comprises a loose tube, a plurality of optical fibers are arranged in the loose tube, and fillers in the tube are filled between the loose tube and the optical fibers.

The flame-retardant belt is further improved in that a flame-retardant sheath material is pressed into a rectangular plate, and a magnesium-aluminum flame-retardant film is attached to the plate through glue.

In the further improvement, a plurality of holes are uniformly distributed in the foaming cushion layer and the flame-retardant sheath by taking the center of the optical cable as a central point, and nitrogen is injected into the holes.

Further improved, the density of the foaming cushion layer is less than 0.8g/cm³The material is extruded.

A preparation method of a flame-retardant low-release object layer stranded optical cable comprises the following steps:

1) stably releasing the optical fiber through a pay-off rack, wherein the pay-off tension of the optical fiber is less than 80N, curing the optical fiber through a coloring mold and a curing channel, removing static electricity through a static electricity removing device, and collecting the colored optical fiber on a disc;

2) a plurality of colored optical fibers are steadily released through active paying-off, the paying-off tension is 80N-100N, a PBT loose tube is extruded outside the optical fibers while paying-off is carried out, an optical fiber unit is formed, the paying-off tension can be properly adjusted according to the surplus length of the loose tube, and the surplus length is 0-0.5 per mill; wherein the extrusion molding process adopts a temperature difference method for production, and in order to ensure the full crystallization of a product, the product needs to be cooled by a hot water tank and a cold water tank which are arranged in front and at the back, the water temperature difference of the cold water tank is 45 ℃, the temperature difference is controlled within 5 ℃, the hot water tank is set to be 60 ℃, and the cold water tank is set to be 15 ℃; the hot water tank is internally provided with a section of annular pipeline, four water outlets which are evenly distributed according to 360 degrees and are provided with pressure regulating valves are arranged in the pipeline, water pressure impact is carried out on the PBT loose tube at the hot water tank section, the pressure regulating valves ensure that the water flushed out from the water outlets has controllable pressure, the water pressure impact is used for increasing the extra length of the PBT loose tube at the hot water tank section, the length of the cold water tank is set to be 25 m, 2 turning guide wheels are added for fully cooling and crystallizing, the cooling length of the loose tube is expanded to be more than 100 m, the full crystallization of a product is ensured, and the influence of 2 times of crystallization on the extra length again is avoided;

3) the reinforced structural member, the optical fiber units and the cable opening rope are twisted into a cable core through a twisting machine, and stable paying-off is carried out through a paying-off device, wherein the paying-off tension is not larger than 180N;

4) the metal composite belt for embossing treatment is wrapped outside the cable core, and the size of the forming grinding tool for embossing treatment is as follows: the diameter of the cable core is +1 mm;

5) wrap the fire-retardant area on metal composite belt, wrap the package overlap joint for 5% around the package pitch, and the cable core after wrapping passes through mold core, die sleeve and gets into the extruding machine aircraft nose and carry out the extrusion molding, and the extrusion molding material is medium density PE material, and the heating section divides multistage fuselage and multistage aircraft nose, and the fuselage temperature is respectively: 130 ℃, 140 ℃, 150 ℃, 155 ℃ and 160 ℃, and the head temperature is respectively as follows: at 170 ℃, 170 ℃ and 180 ℃, the cable core is dragged through a central hole of a mold core during production, 12 core pipes are arranged on the mold core around the central hole, 12 corresponding holes are formed in the foaming cushion layer after extrusion molding in a pipe extrusion mold mode, 12 corresponding injection pipes are arranged on a pressure mold gun, nitrogen is quantitatively injected into the corresponding holes through pressure control, the foaming cushion layer is formed after cooling through a cooling water tank, and a finished product is collected on a disc;

6) the cable core that contains the foaming bed course with above-mentioned extrusion molding carries out steady unwrapping wire through pay-off, and unwrapping wire tension is not more than 180N, and the cable core that contains the foaming bed course passes through mold core, die sleeve and gets into the aircraft nose and carries out the extrusion molding, and the extrusion molding material is the fire-retardant PE of low release amount, and the heating section divides multistage fuselage and multistage aircraft nose, and the fuselage temperature is respectively: 150 ℃, 170 ℃, 180 ℃, 190 ℃ and 200 ℃, and the head temperatures are respectively as follows: the production process includes drawing the cable core through the central hole of the mold core, extruding 12 pipe cores around the central hole, forming 12 holes in the foamed cushion layer, injecting nitrogen gas via pressure control into the holes, cooling in water cooling tank and collecting the product in the disc.

Further improved, in the step 6) and the step 7), the mold core and the mold sleeve are of a pipe extruding structure, a central hole is formed in the center of the mold core, and 12 core pipes are uniformly distributed around the central hole and used for forming holes through extrusion molding.

Further improvement, after the metal composite belt is formed in the step 4), the cable core can be easily pulled out from the metal composite belt.

The invention has the beneficial effects that:

the twisted unit with the 1+6 structure is selected to replace the original structure of a single reinforcing element, the resistance strength of the twisted monofilament is improved, the tensile strength is better than that of the single element, and the dynamic bending radius is smaller than 10 times of the twisting diameter, so that the bending performance of the product is improved;

the mooring rope is positioned between the metal composite belt and the bundle pipe, the metal composite belt, the foaming cushion layer and the flame-retardant sheath can be easily stripped by the mooring rope, 2 stripping is guaranteed to be 2 meters, and the phenomenon of breakage of the mooring rope is avoided;

a plurality of cavities are uniformly distributed in the foaming cushion layer by taking the center of the optical cable as a central point, nitrogen is injected into the cavities, the nitrogen is used for isolating combustion-supporting gas after combustion, and meanwhile, the cavities and the gas injection design reduce the weight of the product and ensure the roundness of the product;

aiming at the change of the application scene of the product and the consideration of construction convenience, the invention carries out simplified treatment on the structure and the weight of the product, and simultaneously increases the characteristics of flame retardance and low-release substances: the protective sleeve is characterized in that nitrogen is filled in the protective sleeve layer and the foaming cushion layer, so that an insulating layer is formed, flame retardance is realized through a suffocation method, a magnesium-aluminum flame-retardant film is attached to the surface of a base material made of flame-retardant PE, a water vapor layer can be formed after combustion, so that the flame retardance is improved, flame-retardant materials are replaced by flame-retardant gas and water, the discharge of released substances after less combustion is realized, the foaming cushion layer and the twisted reinforcing element are designed, the side pressure resistance and the bending resistance of a product are improved, and the applicability of the product is improved.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic structural view of a mold core according to the present invention;

fig. 3 is a schematic structural view of the pressure die gun of the present invention.

Detailed Description

The invention is further described with reference to the following figures and detailed description.

As shown in FIG. 1, the invention relates to a flame-retardant low-release layered stranded optical cable, which comprises a reinforced structural member positioned in the center of the cable, wherein the reinforced structural member is composed of a reinforcing element 4 and a flame-retardant cushion layer 5 extruded outside the reinforcing element; the optical fiber unit comprises a loose tube 3, a plurality of optical fibers 1 are arranged in the loose tube, and fillers 2 in the loose tube and the optical fibers are filled between the loose tube and the optical fibers; a metal composite tape 8 is wrapped outside the optical fiber units, and cable core fillers 6 and an opening rope 12 are filled in gaps between the optical fiber units and the metal composite tape; the metal composite belt is externally wrapped with a flame-retardant belt 9, the flame-retardant belt is formed by pressing a flame-retardant sheath material into a rectangular plate, a magnesium-aluminum flame-retardant film is attached to the plate through glue, and after combustion, the magnesium-aluminum flame-retardant film can form a water film to be attached to the flame-retardant plate; the flame-retardant cable sheath is characterized in that a foaming cushion layer 7 is extruded outside a flame-retardant belt, a flame-retardant sheath 11 is extruded outside the foaming cushion layer, medium-density PE materials are adopted for the foaming cushion layer and a flame-retardant sheath substrate, the like materials ensure that the adhesive tearing force after extrusion molding is larger than 80N, a plurality of holes 10 are uniformly distributed in the foaming cushion layer and the flame-retardant sheath by taking the center of an optical cable as a central point, nitrogen is injected into the holes, so that an isolation layer is formed, flame retardance is realized by a suffocation method, a magnesium-aluminum flame-retardant film is attached to the surface of the matched flame-retardant PE which takes the flame-retardant PE as the substrate, a steam layer can be formed after combustion, so that the flame retardance is improved, the flame-retardant material is replaced by flame-retardant gas and water, the discharge of released matters after less combustion is realized, the design of the foaming cushion layer and a twisted reinforcing element is realized, the side pressure resistance and the bending resistance of the product are improved, and the applicability of the product is improved.

A preparation method of a flame-retardant low-release object layer stranded optical cable comprises the following steps:

1) stably releasing the optical fiber through a pay-off rack, wherein the pay-off tension of the optical fiber is less than 80N, curing the optical fiber through a coloring mold and a curing channel, removing static electricity through a static electricity removing device, and collecting the colored optical fiber on a disc;

2) a plurality of colored optical fibers are steadily released through active paying-off, the paying-off tension is 80N-100N, a PBT loose tube is extruded outside the optical fibers while paying-off is carried out, an optical fiber unit is formed, the paying-off tension can be properly adjusted according to the surplus length of the loose tube, and the surplus length is 0-0.5 per mill; wherein, in order to improve the bending property, PBT with small hardness is adopted, so that the crystallization and the post-shrinkage of the PBT are larger than those of the common PBT, in order to ensure the stability of the surplus length, the production process is properly adjusted, the extrusion molding process adopts a temperature difference method for production, in order to ensure the sufficient crystallization of the product, the PBT needs to be cooled by two sections of water tanks, namely a hot water tank and a cold water tank, the temperature difference of the cold water tank is 45 ℃, the temperature difference is controlled within 5 ℃, the hot water tank is set to be 60 ℃, the cold water tank is set to be 15 ℃, because the post-shrinkage of the PBT is larger, the surplus length needs to be fully crystallized and expanded, if the paying-off tension of an optical fiber is adjusted, the tension fluctuation is larger, the fiber is easy to break, and the crystallization cannot be fully ensured (the optimal temperature of crystallization is 50-60 ℃) if the temperature difference is adjusted; therefore, a section of annular pipeline is arranged in the hot water tank, four water outlets which are evenly distributed according to 360 degrees and are provided with pressure regulating valves are arranged in the pipeline, water pressure impact is carried out on the PBT loose tube at the hot water tank section, the pressure regulating valves ensure that the water flushed out from the water outlets has controllable pressure, the excess length of the PBT loose tube at the hot water tank section is increased through the water pressure impact, the length of the cold water tank is set to be 25 m, 2 turning guide wheels are added for full cooling crystallization, the cooling length of the loose tube is expanded to be more than 100 m, the full crystallization of a product is ensured, and the influence of 2 times of crystallization on the excess length again is avoided;

3) the reinforced structural member, the optical fiber units and the cable opening rope are twisted into a cable core through a twisting machine, and stable paying-off is carried out through a paying-off device, wherein the paying-off tension is not larger than 180N;

4) the metal composite belt for embossing treatment is wrapped outside the cable core, and the size of the forming die for embossing treatment is as follows: the diameter of the cable core is +1mm, and the cable core can be easily drawn out in the metal composite belt after the metal composite belt is formed;

5) wrap in metal composite belt with fire-retardant area, wrap the lapping for 5% around the package pitch, and the cable core after wrapping passes through mold core, die sleeve and gets into the extruding machine aircraft nose and carry out the extrusion molding, and the extrusion molding material is medium density PE material, and the heating section divides fuselage and aircraft nose, and the fuselage temperature is: 130 ℃, 140 ℃, 150 ℃, 155 ℃ and 160 ℃, wherein the first section of the machine body and the second section of the machine body are arranged at 130 ℃ and 140 ℃ for increasing pressure, the third section of the machine body, the fourth section of the machine body and the fifth section of the machine body are arranged at 150 ℃, 155 ℃ and 160 ℃ for ensuring that the PE material enters a molten state, and a pinhole is injected between the third section of the machine body, the fourth section of the machine body and the fifth section of the machine body for injecting nitrogen through pressure so as to ensure complete foaming, and the temperature of the machine head is respectively: 170 ℃ and 180 ℃ and during production, the cable core is dragged through a central hole of a mold core (shown in figure 2), 12 core tubes are arranged on the mold core around the central hole, 12 corresponding holes are formed in a foaming cushion layer after extrusion molding in a tube extrusion mold mode, a pressure mold gun (shown in figure 3) is provided with 12 corresponding injection tubes, nitrogen is quantitatively injected into the corresponding holes through pressure control, and a finished product is collected on a disc after cooling by a cooling water tank;

6) the cable core that contains the foaming bed course with above-mentioned extrusion molding carries out steady unwrapping wire through pay-off, and unwrapping wire tension is not more than 180N, and the cable core that contains the foaming bed course passes through mold core, die sleeve and gets into the aircraft nose and carries out the extrusion molding, and the extrusion molding material is the fire-retardant PE of low release amount, and the heating section divides multistage fuselage and multistage aircraft nose, and the fuselage temperature is respectively: 150 ℃, 170 ℃, 180 ℃, 190 ℃ and 200 ℃, because the extrusion molding material is flame-retardant PE with low release amount, the requirement on the melting point is higher, the first section of the machine body and the second section of the machine body are set at 150 ℃ and 170 ℃ for increasing the pressure, the third section of the machine body, the fourth section of the machine body and the fifth section of the machine body are set at 180 ℃, 190 ℃ and 200 ℃, the PE material is ensured to enter a molten state, and the temperature of the machine head is respectively as follows: the cable core can enter a sufficient melting state at 210 ℃, 210 ℃ and 220 ℃ only when reaching 210 ℃, the flame retardant performance is released, the cable core is dragged through a central hole of a mold core during production, 12 core pipes are arranged on the mold core around the central hole, 12 corresponding holes are formed in a foaming cushion layer after extrusion molding in a pipe extrusion mold mode, a pressure mold gun is provided with 12 corresponding injection pipes, nitrogen is quantitatively injected into the corresponding holes through pressure control, and a finished product is collected on a disc after cooling by a cooling water tank.

It should be noted that, in step 6) and step 7), the mold core and the mold sleeve are in a tube extruding structure, as shown in fig. 2, a central hole is formed in the center of the mold core, and 12 core tubes are uniformly distributed around the central hole for forming holes through extrusion molding.

Aiming at the change of the application scene of the product and the consideration of construction convenience, the invention carries out simplified treatment on the structure and the weight of the product, and simultaneously increases the characteristics of flame retardance and low-release substances: the protective sleeve is characterized in that nitrogen is filled in the protective sleeve layer and the foaming cushion layer, so that an insulating layer is formed, flame retardance is realized through a suffocation method, a magnesium-aluminum flame-retardant film is attached to the surface of a base material made of flame-retardant PE, a water vapor layer can be formed after combustion, so that the flame retardance is improved, flame-retardant materials are replaced by flame-retardant gas and water, the discharge of released substances after less combustion is realized, the foaming cushion layer and the twisted reinforcing element are designed, the side pressure resistance and the bending resistance of a product are improved, and the applicability of the product is improved.

While the invention has been described in terms of its preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.